In some communication systems, a mobile communication terminal receives downlink signals from a base station over a communication channel, and sends feedback indicative of the communication channel to the base station. The base station configures subsequent transmissions based on the feedback. Channel feedback of this sort is used, for example, in Evolved Universal Terrestrial Radio Access (E-UTRA) systems specified by the 3rd Generation Partnership Project (3GPP). These systems are also referred to as Long Term Evolution (LTE) and LTE Advanced (LTE-A).
Channel feedback schemes for LTE and LTE-A systems are discussed, for example, in 3GPP Technical Specification Group Radio Access Network Working Group 1 (TSG-RAN WG1) document R1-105032, entitled “Way Forward on Enhancement for Rel.10 DL MIMO,” Madrid, Spain, Aug. 23-27, 2010; in 3GPP TSG-RAN WG1 document R1-104477, entitled “Higher CSI Feedback Accuracy Proposals for 4/8Tx Rel.10 DL MIMO,” Madrid, Spain, Aug. 23-27, 2010; in 3GPP TSG-RAN WG1 document R1-104474, entitled “Views and Simulation Results on 4Tx Codebook Enhancements,” Madrid, Spain, Aug. 23-27, 2010; and in 3GPP TSG-RAN WG1 document R1-104398, entitled “Further Analysis of Companion Feedback Performance and Feedback Signaling Overhead Reduction,” Madrid, Spain, Aug. 23-27, 2010, which are all incorporated herein by reference.
Other channel feedback schemes are addressed in 3GPP TSG-RAN WG1 document R1-105801, entitled “Way Forward on CQI/PMI Reporting Enhancement on PUSCH 3-1 for 2, 4 and 8 TX,” Xian, China, Oct. 11-15, 2010; in 3GPP TSG-RAN WG1 document R1-105189, entitled “CQI Enhancement for 4Tx,” Xian, China, Oct. 11-15, 2010; in 3GPP TSG-RAN WG1 document R1-105412, entitled “Enhancing MU-MIMO CQI,” Xian, China, Oct. 11-15, 2010; and in 3GPP TSG-RAN WG1 document R1-105656, entitled “Further discussion on CQI/PMI enhancement,” Xian, China, Oct. 11-15, 2010, which are incorporated herein by reference.
The description above is presented as a general overview of related art in this field and should not be construed as an admission that any of the information it contains constitutes prior art against the present patent application.